1. Field
The following description relates to methods and apparatuses to generate a volume-panorama image.
2. Description of Related Art
Various types of medical equipment for diagnosing patients are currently in use or development. An ultrasonic imaging apparatus, a computed tomography (CT) apparatus, and a magnetic resonance imaging (MRI) apparatus are examples of medical devices often used to generate an image of a cross section of an inner portion of a target, such as, for example, a human body. These medical devices are used often in this capacity due to the relative convenience offered to a patient being scanned by these devices and the speed with which a result from the scan may be obtained. Ultrasonic imaging apparatuses transmit an ultrasonic signal toward a predetermined point of the inner portion of the target and obtain an image associated with the inner portion of the target based on information contained in an ultrasonic signal reflected by the inner portion of the target. As such, ultrasonic imaging apparatuses are relatively compact and inexpensive, capable of real-time display, and relatively safe as radiation exposure is not an issue.
Further, medical equipment has been developed that allows for the output of a three-dimensional (3D) image of the inner portion of the target. Moreover, methodology of creating a 3D panoramic image with respect to the inner portion of the target by synthesizing a plurality of 3D images into a 3D volume image has been developed to secure a larger observation region.
However, the 3D volume image may be limited with respect to providing a wide field of view. For example, an ultrasonic 3D volume image generated from an ultrasonic signal may be limited in terms of the size of a field of view by a type of probe, a configuration of transducers, a number of transducers, and the like. The field of view denotes an ultrasonic image that is obtained from a predetermined area on the target on which a probe is placed, without changing the location of the probe. For example, when a 3D volume image generating apparatus can see an observation area at a depth of about 15 cm from the skin of a target and a viewing angle of 60 to 100 degrees at one moment, a 3D volume image output from the 3D volume image generating apparatus may be limited in being used to observe organs of the target or an entire fetus at one time.
Accordingly, a wide field of view may be secured by combining a plurality of sequentially obtained 3D volume images to generate a volume-panorama image. When a volume-panorama image is generated by combining a plurality of 3D volume images, the 3D volume images are matched. In general, this matching is performed based on a conversion relationship between volume images. The conversion relationship may denote matching of the second volume image to the first volume image by moving locations and orientations of voxels included in the second volume image.
However, a conversion relationship between two or more of the plurality of volume images may cause an error to occur with respect to a conversion relationship between the other volume images. For example, when a volume-panorama image is generated by combining a first volume image, a second volume image, and a third volume image that are sequentially obtained, an error generated with respect to a conversion relationship between the first and second volume images may cause an error to occur with respect to a conversion relationship between the second and third volume images.